The present invention relates to the construction sector, in particular that of slabs for industrial floors and, more particularly, concerns a device which is used for equipping expansion joints between adjacent slabs.
In this description, the word “joint” is used exclusively to denote the zone or space between two adjacent slabs while, in the area of construction, this term is generally used to refer to the device itself which occupies such a zone.
Devices for equipping expansion joints are known in the area of concrete structures. The effect desired from this type of device is to form a connection between adjacent slabs while at the same time allowing limited movement of one slab relative to the other in the plane of the slabs, said movement being due essentially at first to the shrinkage of concrete during setting and subsequently, after setting, to thermal expansion and contraction. The devices are supposed to ensure the transfer of loads between adjacent slabs and to preserve the planarity of the slabs as a whole while avoiding fractures and damage at the edges of the slabs.
The device is to be designed to allow quick and easy placement during the casting of the concrete slabs. It should likewise ensure that the edges of the slabs have sufficient mechanical resistance to rolling stresses, i.e. stresses resulting from vehicles rolling over the slabs, and the like.
A first known solution in the prior art uses sliding dowels which cross the joint and penetrate into the concrete on both sides and which can be provided with armoring reinforcements. These are rather complex systems which are difficult to place and to keep in place during the casting of the slabs. In particular, there is a difficulty in keeping the dowels parallel to each other during installation on site.
The following documents are related to devices which use dowelling. Document WO0134912 is related to an expansion joint between concrete slabs, characterized in that at least two dowels are retained by one runner that substantially divides adjoining concrete slabs. Document U.S. Pat. No. 2,349,983 is related to a device for dowelling transverse joints of concrete road pavements. Document U.S. Pat. No. 2,138,817 is related to a road joint equipped with a pair of spaced members having alternating feet sections, and dowels penetrating the road joint.
Another device uses load transfer plates, which are placed underneath the joint in such a way as to extend from one edge of said joint to the other and which are provided with anchoring elements. One disadvantage is that it is difficult to align individual plates along a rectilinear joint. Moreover, this type of device does not provide any reinforcement of the upper part of the joint, referred to as “lips of the joint” in the technical jargon.